Public Drinking Water Program
Minnesota Department of Health

Source Water Protection for New Community Wells

Download a print version of this document: Source Water Protection for New Community Wells (PDF: 125KB/2 pages)

Community wells provide drinking water to residents of municipalities, mobile home parks, housing subdivisions, and facilities such as colleges, universities, and correctional institutions.  In Minnesota, about 35 to 40 community water supply wells are constructed annually.  Source water protection for a new community well starts as soon as it is proposed to the MDH.  There are several steps that must be followed before a new well can be connected to a community water supply system

Step 1 - Plan review in which the construction specifications for the new well are submitted to the Minnesota Department of Health (MDH) for approval.  MDH staff review them to ensure that the proposed construction meets state well design and plumbing standards and that the proposed construction materials such as the well casing, water supply piping, valves, etc. meet state standards. 

Step 2 – Approval of the site for the new well.   MDH must approve the location for a community water supply well before construction can occur.  The public water supplier must provide documentation that it has ownership or control for all property within 50 feet of the proposed well. Furthermore an estimate of the area that may supply groundwater to the well and an evaluation of the potential contamination sources that could impact the well must be submitted.  MDH uses this information when staff visit the proposed construction site to identify whether it meets the mandatory setback distances from potential contamination sources and that there are no apparent potential sources of groundwater contamination that may result in the well water not meeting water quality standards.

Step 3 – Inspection of well construction and well construction materials.  MDH staff visit the site when the well is being constructed to ensure that the approved construction specifications and construction materials are used.  Any changes to the original approved specifications must be approved by MDH.

Step 4 – Final Inspection of the well and plumbing.  The MDH community water supply engineer who works with the public water supplier to ensure that state and federal drinking water regulations are met conducts a final inspection once the new well is connected to the community water supply system.  A water sample is collected an analyzed for the contaminants that are regulated under the federal Safe Drinking Water Act to ensure that it meets potability standards.  Finally, MDH assigns a vulnerability rating to the well which affects the frequency at which it is monitored for contamination and sets priority for the community to develop or amend its wellhead protection plan.

Too Good to Be True?

Ideally, the previous steps will proceed in an orderly manner but not always.

The Best Laid Plans . . .

American folklore has mention of Murphy’s Law, which states “If something can go wrong it will and at the worst possible moment.”  Constructing a well is not without its challenges and the source water protection steps described above may have to be repeated before a new well is connected to a community water supply system.  Here are some of the common reasons for this:

The new well may not end up being constructed at the original, approved location or it may not use the anticipated aquifer.  Sometimes, geological conditions are different than expected and the aquifer will not produce an adequate supply of water once the well is drilled.  A new location may be needed or the well must go to a deeper aquifer and the construction may need to be modified.  Both of these changes require MDH approval before the community may proceed.

The aquifer may have sufficient yield but the groundwater contains naturally occurring contaminants, such as arsenic or radium that require expensive treatment to meet federal Safe Drinking Water Act requirements.  Other times, the levels of unregulated contaminants such as iron or manganese create a taste or odor problem.   Naturally occurring water quality may result in the community not using the new well or using it as a standby well because it wants to avoid the costs of removing these elements.  If this is the decision, the community has to start all over to find a location for another new well.

Speaking of Plans

The MDH requires that municipalities develop a wellhead protection plan or amend an existing wellhead protection plan when a new community well is added to the water supply system.  This helps ensure that local and state efforts to prevent or remediate groundwater contamination recognize the new well.  State wellhead protection regulations prescribe how plan development and implementation are to occur and involve considerable effort on the part of the public water supplier, MDH, and other agencies.  Given the uncertainties that may be encountered with actually constructing a new well, it would be risky to invest public resources in developing a wellhead protection plan for a proposed well.  Therefore, wellhead protection plans are only developed for new community water supply wells once they are actually connected to a public water supply system.

Questions?

Call the Drinking Water Protection Section at 651-201-4700.

Updated Monday, 06-Jun-2011 14:11:56 CDT